As is well known, hair is composed of a unique protein material, called "keratin", which is distinguished by the fact that it contains a very significant amount of an amino acid (cystine) which contains the element sulfur in addition to the elements nitrogen, oxygen, carbon and hydrogen. In the structure of hair, the cystine covalently links polypeptide chains, inter and intra molecularly, (K) through two sulfur atoms (S-S). These disulfide bonds can be broken only by specific chemical action.
Similarly, it is well established that in order to permanently wave hair this disulfide linkage must be broken. In this regard, many prior art compositions have been developed for the "cold permanent waving" of hair. Typically, these prior art systems treat the hair with a reducing agent which breaks the disulfide (cystine) linkages in the hair while the hair is wound around a curling rod.
The reducing agent typically employed is a mercaptan. The chemistry involved in the reaction of a mercaptan with the cystine disulfide bonds in the hair fiber is illustrated by the following chemical equation: EQU KSSK+RSH.revreaction.2KSH +RSSR
By rebonding the sites in the reduced keratin in their new curled configuration, a permanent set which is impervious to water is established.
The rebonding of the reduced sites is accomplished by the action of a chemical oxidizing agent, commonly referred to as the permanent wave neutralizer. Typically, the oxidizing agent used in most neutralizers is hydrogen peroxide, and its chemical reaction is illustrated in the following equation: EQU 2KSH+H.sub.2 O.sub.2 .fwdarw.KSSK+2H.sub.2 O
A problem encountered with the use of mercaptan reducing agents for the permanent waving of hair is that one lotion strength is needed for normal hair while a different lotion strength is needed for damaged or difficult to wave hair. This problem is further compounded when there is damaged as well as normal hair on a head of hair to be permanently waved.
In general, damaged hair fibers and relatively undamaged hair fibers coexist on almost every head. Since the hair grows outwardly from the scalp, it is constantly being subjected to mechanical damage, particularly from the normal grooming process of shampooing, combing, drying, and brushing. In addition to this physical damage of hair, hair is also damaged by chemical action such as by exposure to sunlight and contact with water containing chlorine. Also, the repeated use of permanent waving compositions on the hair fibers may cause damage to the hair especially if not used according to directions.
Damage to the hair fiber by other than chemical service is almost entirely directed against the hair cuticle. In shampooing, for example, it is the actual physical manipulation of the hair, rather than the shampoo itself, which causes the majority of the damage. In normal hair, which has six to seven cuticle layers at the new growth or scalp area, studies have shown that a normal shampoo process can break away the cuticle at the rate of 1 to 2.5 cuticles for every fifty treatments. Since it is not unusual for a woman to shampoo her hair every day, it is therefore possible that she could lose up to seven cuticle layers of her hair in five months.
Since hair normally grows approximately one-half inch each month, it is apparent that in five months, all of the hair longer than two and one-half inches would be denuded of the cuticle layer. In addition, since the cuticle comprises ten percent or more of the hair fiber, and a much higher percentage in fine hair, and is intended to act as a protective sheath about the cortex, its complete destruction represents formidable damage to the hair fiber. Once the hair fiber has lost part or all of its cuticle, it is classified as porous and readily absorbs any aqueous solution applied to it.
Bleached hair is particularly difficult for the successful application of cold permanent wave solutions because the bleached hair fibers have a substantially reduced cystine level and are usually very fragile. Bleached hair is often characterized as being dry, brittle, and overly coarse.
As a result, special precautions are usually taken to protect bleached hair when a permanent wave solution is to be applied. These conventional precautions include the application of a pre-conditioner before the permanent wave solution is applied, along with the use of a specially formulated permanent wave lotion.
Another prior art technique typically employed both for bleached hair as well as all types of hair where diverse conditions exist along the hair fibers is the use of end wraps. For most permanent wave applications, a tress of hair is wrapped about a cylindrical rod or curler. However, since difficulty is often encountered in wrapping the free ends of the hair tress on the curler, a small square or rectangular piece of paper, commonly referred to as "end wraps" are folded over the ends of the hair tress in order to make the hair more controllable and more easily rolled about the curler.
In an attempt to eliminate the inherent difficulty encountered from overprocessing and underprocessing the various segments of the hair during a permanent wave application, various conditioning compositions have been applied to the end wraps so that the ends of the hair fibers are treated separately, by coming directly in contact with the end wraps. Such compositions as oils, lanolins, diluted waving lotions, conditioners and vitamin compositions have all been employed in the end wraps in an attempt to prevent the undesirable overprocessing of the hair ends.
In addition, the use of permanent wave lotions may cause damage to the hair fibers especially if directions are not followed. As a result, uniform results become increasingly difficult the more frequently a particular head of hair is permanently waved.
In spite of the extensive effort directed to the protection of the hair ends and to bleached hair, as well as to conditioning of the hair fibers prior to applying cold permanent waving compositions, none of these prior art systems have achieved the desired results. In general, typical prior art cold permanent wave lotions have been unable to satisfy the diverse conditions which exist along the length of hair fiber and produce a uniform permanently waved head of hair, with minor increased damage. In general, depending upon the concentration of the lotion applied to the head of hair, particular segments of the hair are either underprocessed or overprocessed, with the adverse appearance resulting therefrom, while the hair fibers are further damaged.
Consequently, it is a principal object of the present invention to provide a single, cold permanent waving composition which simultaneously conditions the hair and produces a substantially uniform permanent wave throughout the head of hair regardless of the damaged condition of portions of the hair fiber.
Another object of the present invention is to provide a unique permanent cold waving composition having the characteristic features described above which substantially reduces the amount of increased damage to the hair fibers caused by the permanent wave lotion.
Another object of the present invention is to provide a unique permanent cold waving composition having the characteristic features described above which can be formulated for various types of damaged hair conditions, thereby assuring an even more effective, uniform permanent wave.
Another object of the present invention is to provide a cold permanent waving composition having the characteristics defined above which is applied easily and conveniently in a single application step, without requiring any special application techniques or extra steps or procedures.
Other and more specific objects will in part be obvious and will in part appear hereinafter.